Difference of complexity between double nested for loops? (Java)

Difference of complexity between double nested for loops? (Java)

What's the difference in terms of performance and complexity between these
two nested for loops?
for(int i = 0; i < l.length; i++) {
for(int j = 0; j <= i; j++) {
//do something
}
}
and :
for(int i = 0; i < l.length; i++) {
for(int j = 0; j < l.length; j++) {
//do something
}
}